Redback Spider

Latrodectus hasseltii, family Theridiidae

Identification

Females black with yellow to red stripe down back, sometimes also with diagonal white stripes on side, and with red hourglass mark under body. Males black with white stripe, no red stripe on top. The legs of males and females are slender, black, pin-like. Length: adults easily span 50c coin.

Distribution

Redbacks are found Australia-wide, although they are less common in wet tropics, and also found in New Zealand, Osaka, Japan. Their natural distribution seems to be South Australia and Western Australia.

They are found in warm or hot sunny spots around northern and western faces of houses, especially barbeques, under tables chairs, around pool edges and in hollow metal pipe fences. Also often found in garages. Webs made in ceilings of houses are often built above inset lights.

Web

Strong fine tangle often with leaves and twigs; lower part of web with few sticky lines, female and egg sacs in upper funnel like cup protected from rain.

Bite

Potentially fatal.

Only females are known to bite, with a sharp nip followed at varying time intervals by increasing pain and localised patches of sweating. Results of bites are highly variable: the spider has full control over venom dosage and some bites may be "dry", i.e., venom-free defensive bites.

The venom is latrotoxin, which is effective against most animals.

Notes

Main prey: Insects, mice, snakes, small birds, lizards, other spiders.